European Patent Application Publication No. 346999 (EP 346999) discloses a process for the preparation of a lubricating base oil, containing a hydrocarbonaceous product prepared by contacting hydrocarbons and/or derivatives thereof with an active hydrogen-containing system, which process includes generating a hydrogen-containing plasma at a pressure of at least 0.007 bar and allowing contact of the hydrocarbons and/or derivatives thereof in liquid form with the plasma-generated system and recovering the hydrocarbonaceous product.
For the purpose of this specification, a process such as disclosed in EP 346999 will hereinafter be referred to as a plasma-process. The disclosure of EP 346999 is hereby incorporated by reference. It will be understood that the hydrocarbonaceous product referred to throughout the specification is the product of plasma-process. Derivatives as referred to in this specification are defined as hydrocarbons containing heteroatoms, such as sulphur, nitrogen and/or oxygen.
It has now been found that certain lubricating base oil properties of the aforementioned hydrocarbonaceous product, such as dispersancy, cleanliness and/or oxidation stability, can be further and significantly improved by treating the hydrocarbonaceous product with hydrogen at elevated temperature and pressure in the presence of a catalyst.
Moreover, it has been found that in the process of the present invention, other advantageous lubricating base oil properties of the hydrocarbonaceous product, such as a high viscosity, a high viscosity index (VI) and a low pour point remain substantially unchanged or are even slightly improved.